Proximal soil moisture sensing of dairy pasture

A proof-of-concept proximal soil moisture sensor is developed for the precision irrigation of dairy pasture. The proposed sensor, mounted on the boom of an irrigator, measures the soil moisture of ground area in front of the irrigator and feeds the measured moisture data to the variable rate irrigator´s controller. The sensor adopts techniques from the ultrawideband radar, in which the ground´s resolution area is confined by both its antenna beamwidth and transmitted pulse-width. In this paper, we present the sensing methodology, design, prototyping, measurement and results of the proposed sensor. Measured results demonstrate the sensor´s performance in terms of its soil moisture measurement accuracy, and the effects of varying sward heights of pasture grass.